[mythtv-users] Re: Re:LVM & Disk Performance

Eric Thelin eric at generation-i.com
Mon Nov 17 16:48:55 EST 2003


I am assuming that the basis for the recomendation in the email below is
due to the interface speed differences between your cd drive and your
hard drive.  If your CD drive is runs at a slower speed (ATA66 is
common) you may get better hard drive performance by making sure the CD
is on a bus without any hard disks because it will slow the HD to the
same speed.  But the reasoning for keeping the two drives seperate still
stands.  A master and a slave can't both communicate at the same time.
Which means that your OS reads/writes will be taking turns with your
myth reads/writes.  This will cause a significant speed degradation for
disk intensive applications such as mpeg2 playing or recording in myth.
So I stick by the concept that you should never put two devices that you
plan to access simultanously on the same bus.  You would also not want
to put a CD burner and a hard drive you plan to burn from on the same
bus.  I am also a believer in using add in PCI cards to get more ide
channels so you don't have to use slaves to access your devices.

Eric

On Mon, 17 Nov 2003, Harondel J. Sibble wrote:

>
>
> On 17 Nov 2003 at 9:19, Myster Man wrote:
>
> > Well actually back in the ata33/66 days this was true, but from what I
> > understand all modern ata100/133 controllers have resolved this problem.
>
> No actually, that's only true if you are using modern drives, if you have a
> really old hdd or an older cdrom, they WILL Slow the ide bus down.
>
>
> > In the case here you have to either have the two hard drives on the same
> > channel or a hard drive and cdrom on the same channel. I would say that
> > the layout you have suggested would be the best.
>
> Put both hdd's on the same channel (assuming one of them is not acient) and
> the cdrom on it's own.
>
>
>
>


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